Ductile ruthenium alloy and process for producing the same



United States Patent Ofiice 3,362,799 Patented Jan. 9, 1968 ABSTRACT OFTHE DISCLOSURE The ductility of ruthenium produced by powder metallurgyis improved by mixing ruthenium powder with 0.1% to 25 of rhenium powderand consolidating the mixture to form an alloy product.

The present invention is directed to a process for producing by powdermetallurgy methods a ruthenium product characterized by improvedductility and to the ruthenium product produced by the said process.

Ruthenium is a refractory metal normally produced as a powder by thereduction of a salt or compound of the element. When the metal isrequired in a consolidated form, the powder may be melted and cast ormay be compacted and sintered by conventional powder metallurgicaltechniques. By whichever method the consolidation is effected, theresultant metal is not readily workable.

We have now discovered a means whereby the ductility of a rutheniumproduct produced by powder metallurgy can be susbtantially increased.

It is an object of the present invention to provide a powder metallurgymethod whereby the ductility of ruthenium is substantially improved.

It is a further object of the invention to provide a method employingcommercially available materials to produce by powder metallurgyruthenium products having improved ductility.

It is another object of the invention to provide ruthenium powdermetallurgy products characterized by improved ductility.

Other objects and advantages of the invention will become apparent fromthe following description.

According to this invention, ruthenium produced by powder metallurgicalmethods is alloyed with a lesser amount of rhenium and it is found thatthe resultant alloy has much improved ductility. This is very surprisingsince if ruthenium is alloyed with rhenium by melting, no improvement inductility is obtained, although there is some decrease in hardness whenthe amount of rhenium added is small. Again, if zinc, for example, isadded to ruthenium by melting, there is some improvement in ductilitybut none is obtained if zinc is added to powder metallurgically producedruthenium.

As little as 0.1% rhenium improves the ductility of ruthenium but,advantageously, about 0.25% to about 2.5% of rhenium is employed.Substantially greater amounts of rhenium, say or even 25%, can beincluded in the alloy if desired. A further advantage of the alloys ofthe invention lies in the fact that they increase in ductility afterrecrystallization.

In producing the alloys, ruthenium powder and rhenium powder may bethoroughly mixed and pressed to compacts in flexible bags under apressure of, say, 8 to 10 tons per square inch. The resultant compactsmay be sintered, for instance at 1450 C. for 8 hours in vacuo, and hotrolled at the sintering temperature to sheet. The

thickness may be reduced by 3% at each pass. Sheets of dilierent rheniumcontent made in this way and each 0.02 inch thick were vacuum annealedat 1450 C. for 8 hours, and then subjected to tensile tests and tobending tests on a Galileo Rigidometer. The results obtained were asfollows:

Ultimate Bend Alloy Tensile Test 2 Strength 1 (degrees) Pure Ru 0.8-70.5% Re, balance Ru 20 20 2.0% Re, balance Ru 22 15 10.0% Re, balance Ru26.8 17 20.0% Re, balance Ru. 26.1 12

1 Tons per square inch. 2 Angle of plastic deformation before cracking(span length=10 mm.).

The results of bend ttests on apparently identical samples of pureruthenium vary unaccountably within the range given above. Generallyspeaking, the angle of plastic deformation does not exceed 2 and valuesas high as 5 or 7 are obtained only exceptionally.

The alloys according to the invention consist simply of ruthenium andrhenium except for any impurities which may be present. Commerciallyavailable powders may be employed to produce the special productscontemplated in accordance with the invention.

The ductility of the alloys according to the invention is such that theycan be used as sparking plug electrodes, since they can be readily bentto adjust the size of the spark gap in the sparking plug. Moreover, thealloys according to the invention have better resistance to attack bylead than has iridium, commonly used as such an electrode.

The alloys are also useful for the construction of other articles andparts that require great resistance to corrosion and are made by hot orcold forming. Examples of such articles are crucibles for handlingcompounds containing phosphorus, repair plugs for glass lined vesselsfor handling corrosive materials, and facings for soldering iron bits.In the last mentioned use, the combined properties of resistance tooxidation and resistance to attack by molten metal are of particularadvantage.

Although the present invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the invention and appended claims.

We claim:

1. The process for improving the ductility of rutheniurn which comprisesmixing ruthenium powder with rhenium powder to produce a powder mixturecontaining about 0.1% to about 25% by weight of rhenium, with thebalance essentially ruthenium, compacting and sintering said powdermixture to form a consolidated ruthenium product and hot working saidconsolidated product to form a ruthenium shape having improved ductilityas compared to a similar ruthenium shape produced from ruthenium powderalone.

2. The process according to claim 1 wherein the initial powder mixturecontains about 0.1% to about 20% rhenium powder.

3. The process according to claim 1 wherein the initial powder mixturecontains about 0.1% to about 10% rhenium powder.

4. The process according to claim 1 wherein the initial powder mixturecontains about 0.25% to about 10% rhenium powder.

5. The process according to claim 1 wherein the initial powder mixturecontains about 0.25% to about 2.5% rhenium powder.

6. A ruthenium alloy powder metallurgy product having improved ductilityand containing about 0.25% to about 2.5% by Weight of rhenium with thebalance being essentially ruthenium.

7. A ruthenium alloy powder metallurgy product having improved ductilityand containing about 0.1% to about 25% by weight of rhenium with thebalance being essentially ruthenium.

8. A ruthenium alloy powder metallurgy product having improved ductilityand containing about 0.25% to about 10% by weight of rhenium with thebalance being essentially ruthenium.

References Cited UNITED STATES PATENTS Noddack et al 29-192 X Weiger75-134 X Pinkus 29-182 Hensel 75-172 X Smithells 75-172 X Middleton29-182 X Streicher 75-200 X Hall et al 75-200 X CARL D. QUARFORTH,Primary Examiner. M. I. SCOLNICK, Assistamz Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,362,799 January 9, 1968 Bryan Jones et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

In the heading to the printed specification, line 10, after "19,959/64"insert Complete specification, Apr. 29, 1965 column 2, line 19, for"ttests" read tests Signed and sealed this 18th day of February 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Ir.

Attesting Officer

